Drill bit



J. J. BROSSOIT.

DRILL BIT.

APPLlCATlON FILED MAR. 22. 1921.

PatentedSept. 5, 1922.

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' A TTORIVEYS Patented Sept. 5, 1922.

' UNITE srras PATENT OFFICE.

JAMES JOSAPH BROSSOIT, 0F SALT LAKE CITY, UTAH.

DRILL BIT.

Application filed March 22,. 1921. Serial No. 454,376.

of Salt Lake City, in the county of Salt Lake and State of Utah, haveinvented a new and Improved Drill Bit, of which the following is a full,clear, and exact descrip- This invention relates to drills, and hasparticular reference to a new and improved cutting surface for drills.

An object of the invention resides in the provision of means whereby thecutting surface of a drill shank or holder may be readily removed to besharpened and be readily replaced.

Another object resides in the provision of a simple and eflicient meanswhereby the removable cutting surface may be attached to the drill shankvery readily and be firmly locked therein.

A further object resides in the particular construction and arrangementof parts which are hereinafter described and claimed and shown in theaccompanying drawin s.

In arts where drills are used, especiaIly in mining and in rock'drilling, it has been hitherto necessary to provide a great number ofdrills, for the simple reason that during their operation a certainpercenta e of the drills had to be constantly out 0 use to beresharpened. This necessitated the expenditure of considerable time andmoney and the waste of a certain percentage of the drills from actualuse during the time they were withdrawn for this purpose.

My invention resides particularly in providin a cutting surface orportion of the drill s ank removable in a' simple and ready manner sothat a number of them can be carried around, for instance in a minerspocket, and be placed in the shank as others are removed to beresharpened. This eliminates the necessity for having a larger number ofdrills than are actually in constant use, and merely necessitates havingthe reuired number of cutting portions on hand. It is a- .simple matterto take these small cutting portions and have them sharpened as deslred.

The invention is shown in the drawings, of which- Figure 1 is a sideelevation of the drill shank and cutting portion parts being brokenaway;

Figure 2 is a section taken on the line of Figure 1; Figure 3 is aninverted plan view of 1; j 1 ;igure 4 is a plan view of the r taining pa e' Figure 5 is a partial section of a modiijied form of drill shankand cutting surace.

The preferred embodiment of my invention, as shown in the drawings,comprises a drill shank 1 the lower surface of which is provided with agroove 2 having tapered side walls 3. In this groove 2 a cutting portion4 is disposed having similar tapered side portions and a cutting edge 5.In-- specting the inverted plan view shown in Fig. 3, it will beobserved that the longitudinal lines 6 and 7 indicating the abuttingedges of the cutting portion 4 and the groove 2, are tapered and wedgeshaped. Between the upper face 8 of the cutting portion 4 and thesurface of the groove 2 is a retaining or fastening plate 9.

The drill shank 1 and the cutting portion 4 are both of hard steel,whereas the retaining plate 9 is made of some softer metal. When thecutting portion 4 is to be placed into the drill shank 1, the retainingplate 9 is placed in the position shown in Flg. 2 and the cuttingportion is then slipped into the groove and becomes wed ed therein, dueto the tapered ed es 6 and 5 above mentioned. As shown in I ig. 1, oneupper edge of the cutting portion 4 is provided with a beveled shoulder10, and a slmilar beveled shoulder 11 is provided on the shank. When thecutting portion 4 is in position, the ends of the soft metal of theretaining plate 9 are ham-. mered down, as shown at 12 in Fig. 1, so asto lock the cutting portion 4 in position. The fact that the surfaces ofcontact between the retaining plate 9 and the shank 1 and the cuttingportion 4 are between soft and hard metal makes this such a contact aswill insure the proper amount of friction therebetween to hold theportions together, in addition to the other retaining means mentionedabove.

In Fig. 4 is shown a view with the retain-- ing plate 9 tapered inaccordance with the taper of the groove 2 above mentioned.

In Fig. 5 a cutting portion 4 quite similar to the one above mentionedis provided having in its upper surface near one end thereof a recess 13with which the lower end 14 of a lock pin 15 pivoted at 16 in a groove17 on the shank 1, is adapted to engage. When this engagement occurs, apin 18 is driven sharpened. They are preferably made of drop-forgedmetal, are small and light. and may be carried on the person withoutinconvenience. This invention will be of great advantage in manyoperations, eliminating the distribution of the steel throughout themines. By means of this invention it is not necessary to remove thedrills from the place of working.

What I claim is:

1. A drill having a shank portion provided with a tapered recess in itslower edge, a similarly tapered cutting edge adapted to be disposed insaid recess, and a retaining plate disposed between the cutting portionand the inner face of the recess, said plate being of soft metal theends of, which are adapted to be hammered to lock the cutting portion inthe recess.

2. A drill comprising a shank portion having a recess therein, saidrecess being tapered vertically and longitudinally, a cutting portionadapted to be inserted in. said recess and provided with similarlytapered faces, said shank and cutting portions being of hard metal, aretaining plate of softer metal disposed between the inner faces of thecutting portion and the recess, a beveled surface on the shank at oneside, and a beveled surface on the cutting portion at the other end, theends of the soft metal retaining plate adapted to be hammered to engagethese beveled edges and lock the retaining plate and the cutting portionin the recess.

3. A drill having a shank portion provided with a recess in its loweredge, a cutting edge or tool disposed in said recess,-a retaining platedisposed between the cutting tool and the shank portion, and means on'said plate for locking the cutting tool in the recess.

4:. A drill having a shank portion provided with a recess in its lowerface, a cutting tool to be disposed in said recess, and means disposedentirely between the bottom of the recess and the adjacent .face of thecutting tool to lock the tool in the recess.

5. A drill comprising a shank portion having a recess therein, saidrecess being tapered vertically and longitudinally, a cutting portiondisposed in said recess and provided with similarly tapered faces, aretaining plate of soft metal disposed between the inner faces of thecutting portion and the recess, an upwardly beveled surface on the shankat the small end of the tapered recess, and an outwardly beveled surfaceon the cutting portion at the larger end of the recess, the ends of thesoft metal retaining plate being distorted by hammering to engage thesebeveled edges andlockthe retainmg plate and the cutting portlon in therecess.

JAMES J OSAPH BROSSOIT.

